JP2006073589A - Wiring board and its manufacturing method, semiconductor package, and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board having a high degree of freedom of designing in the depthwise direction with respect to the front surface of the board as shown by having such portions as side faces of shield interconnections having a coaxial line structure and interlayer interconnections of a multilayer wiring board. <P>SOLUTION: A metal is used for a core substrate. The core substrate is photo etched, and then an insulation resin is cast, and lamination is performed at least once, or twice or more, to form the side faces of shield interconnections having a coaxial line structure and interlayer interconnections of a multilayer wiring board. The coaxial line structure is such that a signal line is surrounded by an insulation resin layer and then the insulation resin layer is coated with an annular shield electrode. It is preferred that interlayer connection is performed between top and bottom faces of the shield electrode which is perpendicular to the signal line having the coaxial line structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-density wiring board, and relates to a wiring board that uses a metal layer as a core board, a manufacturing method thereof, a semiconductor package, and a printed wiring board.

  In electronic information systems, the signal frequency handled is higher, and the density of wiring boards is also increasing. In the conventional wiring board, when the wiring pattern consisting of signal lines is close, crosstalk noise, noise radiated from the signal transmission line or external noise is generated between the wiring patterns, causing malfunction of the circuit drive element There are things to do.

  In order to prevent this, conventionally, a means has been proposed in which a shield wiring is provided adjacent to a signal line pattern and a reference potential of a power supply line or a ground line is applied to the shield wiring. In an actual high-density printed wiring board, a strip line or a microstrip line is generally used as a signal line structure. In this stripline and microstripline structure, since the electromagnetic field generated from the wiring spreads laterally along the shield surface, it is difficult to sufficiently block the wiring signal crosstalk and external noise.

  In order to solve the above problems, there is a printed wiring board having a coaxial wiring structure. By adopting a coaxial wiring structure in the printed wiring board and confining the electromagnetic field generated from the signal line inside the coaxial shield structure, the system for signal crosstalk between wires and external noise is dramatically improved. .

The known literature is described below.
JP 2003-249731 A

  However, in the manufacturing method of the coaxial wiring structure, the yield decreases due to the leftover of the insulating resin left in the process of metal plating on the grooved portion, and the adhesion between the insulating resin and copper occurs, resulting in connection reliability. There arises a problem that the performance is lowered. Also, if you have grooves and vias with different shapes other than coaxial wiring on the same substrate surface, and fill the grooves and vias with metal plating, use a special plating solution or perform plating treatment for each substrate shape. It must be done separately. When an attempt is made to make the coaxial wiring structure multi-layered by this method, it is difficult to perform the plating process simultaneously on the interlayer wiring portion of the signal line and the side surface portion of the shield wiring portion.

  The present invention has been made in view of the above problems, and provides a coaxial wiring structure with a rectangular cross-sectional shape that reduces noise generated between the wiring patterns of signal lines of a high-density wiring board. Wiring with a high degree of design freedom in the depth direction with respect to the substrate surface, such as the side of the shield wiring part of the coaxial wiring structure and the interlayer wiring part of the multilayer wiring board, for the purpose of improving the quality of wiring and simplifying the process in the manufacturing method It is an object of the present invention to provide a substrate and a manufacturing method thereof.

The present invention solves the above-described problems, and has a structure in which a metal is used as a core substrate, and this is formed by repeating photoetching, casting of insulating resin, and bonding at least once or twice or more. A wiring board,
It has a coaxial wiring structure in which the signal line is surrounded by an insulating layer and the outer side is covered with an annular shield electrode. A wiring board characterized in that
And, within the same substrate plane, there are a plurality of types of wiring diameters of the shield electrode portion in the direction orthogonal to the signal wire of the coaxial wiring structure,
In addition, the wiring board is characterized in that the periphery of the coaxial wiring structure is made of an insulating resin,
Moreover, a wiring board characterized in that the periphery of the coaxial wiring structure is made of metal,
In addition, a semiconductor package having a wiring board characterized in that the periphery of the coaxial wiring structure is made of metal,
The printed wiring board having a wiring board characterized in that the periphery of the coaxial wiring structure is made of metal,
Further, the wiring board is characterized in that a capacitor is formed at the coaxial wiring structure connection portion of the wiring board, wherein the periphery of the coaxial wiring structure is made of an insulating resin,
Further, a semiconductor package characterized in that a capacitor is formed in the coaxial wiring structure connection portion,
The printed wiring board is characterized in that a capacitor is formed in the coaxial wiring structure connection portion,
On the other hand, in one preferable method of manufacturing a wiring board having the coaxial wiring structure described above,
Coating the photoresist on the metal foil upper and lower surfaces of the coaxial wiring circuit;
Patterning the upper and lower surfaces of the metal foil so that the shield electrode side surface and the signal line are formed;
A step of forming the upper half of the shield electrode side surface and the signal line by attaching a protective sheet to the lower surface of the metal foil and etching the upper surface at least once,
A step of casting the surface of the etching surface and the upper surface of the metal foil formed in the previous step with an insulating resin;
Removing the protective sheet on the lower surface and forming the shield electrode side surface and the lower half of the signal line;
A step of casting the surface of the etched surface and the lower surface of the metal foil formed in the previous step with an insulating resin;
Polishing the substrate surface to such an extent that the shield electrode side surface part appears;
A process of patterning the upper and lower surfaces of the shield electrode by attaching metal foil to the upper and lower surfaces of the substrate;
Etching process;
A method for manufacturing a wiring board comprising:
In another preferred method of manufacturing a wiring board having the above coaxial wiring structure, in the step of patterning and etching to form the shield electrode side surface portion and the signal line, the first recess Then, the etching surface and the metal layer surface thus formed are coated with an electrodeposition resist or a liquid resist, and exposed and developed so as to open between the side surface portion of the shield electrode and the signal line and the portion where no wiring is formed. A step of performing a second etching,
In addition, in another preferable method of manufacturing a wiring board having the above coaxial wiring structure,
Coating the photoresist on the upper and lower surfaces of the metal foil;
A step of patterning an interlayer wiring portion on the upper surface and an inner layer wiring on the lower surface;
Applying a protective sheet on one side and etching the opposite side,
A process of casting an etching surface and a metal surface made by this process with an insulating resin;
Etching the opposite side to form a wiring pattern of the interlayer wiring part and the inner layer from the same metal layer by photoetching,
A method of manufacturing a wiring board having a multilayer structure in which at least one type of diameter of an interlayer wiring portion exists in the same substrate surface.

  A pattern is formed by etching a metal foil from one side a plurality of times, and the surface and etched surface of the metal foil are cast with an insulating resin, then etched from the opposite surface, and similarly cast with the insulating resin. Then, the insulating resin is polished to the extent that the metal surface comes out, and a metal foil is laminated on one or both sides of the substrate, and pattern formation by etching, casting with insulating resin, and polishing of insulating resin are repeated in the same manner as the above steps. In this case, the metal is used as a core.

  When this structure is employed, a wiring board having a coaxial wiring structure is a preferred embodiment. A conventional method for forming a wiring board having a coaxial wiring structure is a metal wiring pattern that becomes a signal line while leaving a part of the metal layer on one side of an insulating layer formed by laminating a metal layer of a thin film on both sides. The step of laminating the insulating surface of the insulating layer formed by bonding a metal layer on one side to the surface of the insulating layer on which the signal line is formed, and with the signal line approximately in the center, A groove electrode is formed so as to reach the other metal layer from the metal layer, and at least the surface portion where the groove is processed is subjected to metal plating, so that the outside of the insulating layer surrounding the signal line is shielded from the shield electrode. And the step of forming the coaxial wiring structure covered with the step.

  That is, in this method, after the signal line is formed, the side surface portion and the upper surface portion of the shield wire must be filled with metal by metal plating. In this method, there is a possibility that reliability defects due to plating voids may occur in the plating process. Also, when trying to laminate coaxial wiring, the signal wire outlet must be formed on the same surface of the board, and the hole shape of the different sizes such as the shield wire side surface and the signal wire outlet is formed. Filling by plating becomes difficult.

  On the other hand, in the conventional method of creating metal protrusions filled with plating by etching from a metal layer or multiple etchings, protrusions having different shapes and sizes can be formed in a single plane in the same plane. Is possible. In this case, unlike the conventional forming method described above, all metal processing is performed by etching, so there is no risk of reliability failure due to plating voids, and the design of the portion that has been filled with plating becomes free in the past. Since a shape that can be etched is formed as much as possible, even if there are different shapes in the substrate surface, it can be manufactured without any problem.

  A characteristic impedance is a characteristic of the coaxial wiring. If the coaxial wiring has a cross-sectional structure as shown in FIG. 1, the characteristic impedance is expressed by the following equation.

つまり、シールド線の厚み形状にかかわらず、信号線の大きさ形状とそれを囲んだ絶縁材料の大きさ、形状およびその比誘電率が一定であればよいこととなる。そうすると、図３に示すように信号線とシールド配線部の間の絶縁部分のみをエッチングあるいは複数回のエッチングによって加工し絶縁樹脂を埋め込めば良い。このようにすることによって金属を主とした基板を作ることができ、外部からのノイズ防止や、電気的特性の向上を図ることができる。更には金属を主とした構造のため、放熱性が良く、弾性に富んだ基板ができる。

In other words, regardless of the thickness shape of the shield wire, it is sufficient that the size shape of the signal line, the size and shape of the insulating material surrounding the signal line, and the relative dielectric constant thereof are constant. Then, as shown in FIG. 3, only the insulating portion between the signal line and the shield wiring portion may be processed by etching or etching a plurality of times to embed the insulating resin. In this way, a substrate mainly made of metal can be produced, and noise from the outside can be prevented and electrical characteristics can be improved. Furthermore, since the structure is mainly made of metal, a substrate with good heat dissipation and elasticity can be obtained.

By utilizing the feature that a portion that has been filled by conventional plating can be formed by etching, it becomes possible to manufacture a wiring board having a complicated three-dimensional shape that has been difficult to realize so far. For example, it becomes possible to collectively form the lower layer wiring and the interlayer wiring part in the multilayer wiring board from the same metal layer within the substrate surface by photoetching.

  The cross-sectional shape is shown in FIG. Similar to the process of making the side surface of the coaxial cable signal wire and shield wire described above, etching from one side or etching is performed several times, and the same surface is filled with resin, and then the opposite surface is etched or multiple times. Etching process is performed. By changing the position and size of the opening pattern in this process, the lower layer wiring and the interlayer wiring part are created from the same metal layer, and the pattern shape that is the interlayer wiring part has different diameters in the same plane It can be made easy. In the wiring with high density, there is a great demand that the power wiring is formed with a large diameter and the signal wiring is formed with a small diameter. With this method, a coaxial wiring structure having interlayer wiring portions having different diameters can be easily formed on the same substrate surface.

  The wiring board having the coaxial wiring structure of the present invention and the method for manufacturing the wiring board can be obtained by performing photo-etching from the front and back surfaces of the substrate using the metal layer as a core substrate, and obtaining a wiring having an irregular cross-sectional structure, which is cast with an insulating resin or ceramic In addition, a complicated wiring structure can be obtained by stacking. Processes such as coaxial wiring structures that have been difficult to build on the inner layer of wiring boards, shield wiring side surfaces of coaxial wiring structures, and interlayer wiring parts of multilayer wiring boards can be simplified. Can provide a structure that frees design.

  Hereinafter, embodiments of the present invention will be described in detail.

  The present invention provides a wiring board having a complicated three-dimensional shape having a metal layer having a different cross-sectional shape from the same metal layer and a method for manufacturing the same. According to the present invention, coaxial wiring that can be stacked on the upper and lower surfaces, which is impossible with the conventional method, and lower layer wiring and interlayer wiring in a multilayer wiring board can be formed at once. Specifically, the product of the present invention can be used as a high-definition metal etching product such as a flexible substrate, a semiconductor package, and a printed wiring board, and in particular, a wiring board having a coaxial wiring structure, a wiring board having multiple layers, and a high-density wiring. This is an effective method for boards.

  Next, the present invention will be described. The present invention is a product in which a plurality of different metal thicknesses are formed by repeating etching at least twice or more in the film thickness direction of the metal layer serving as the core material of the wiring board. The processed portion is formed by multiple times of etching, and the processed portion has a plurality of side walls using a primary or electrodeposition resist or liquid resist on the surface layer side of the metal layer, and further, from the surface layer side opposite to the metal layer. It has a complicated three-dimensional metal pattern having at least one side wall by etching from both sides due to etching.

  In the present invention, a product having a plurality of metal thicknesses in the same metal layer and having an irregular cross section, which could not be achieved in the past, is provided. It is not a simple shape with just through holes formed as usual, the size of the holes formed from the front surface and the holes formed from the back surface are very different, or concaves are formed on both sides or one side of the metal substrate. It can have a complicated cross section. By having such a shape, for example, it is possible to mount a wiring having a coaxial wiring structure on a wiring board, or in a multilayer wiring board, a lower wiring pattern and an interlayer wiring portion can be made from the same metal layer. Such excellent advantages are obtained.

  Hereinafter, the production method of the present invention will be described in detail. In the method of manufacturing a wiring board having a complicated three-dimensional shape according to the present invention, a three-dimensional and complicated etching shape is obtained by changing the pattern shape of a photomask used for exposure even when high-order etching is performed on the front or back surface or the same surface. Is possible.

  In order to obtain a desired complicated shape, the present invention described above can be obtained through a process of etching from one surface side or after a plurality of etchings, casting the surface with an insulating resin, and etching the opposite surface. . By performing anisotropic etching in the depth direction and etching different patterns from the front and back, a metal pattern having a complicated three-dimensional shape is formed. In order to obtain the wiring board which is the product of the present invention, the metal plate as the core is etched in several steps.

  The wiring board which is the product of the present invention is etched several times on the front and back surfaces or on the same surface, but the photomask used is different. First, a photoresist is coated on both surfaces of a metal substrate to form a resist film. Thereafter, an opening pattern is formed. Exposure and development are performed on a desired position of the resist film, and the resist film at the desired position is removed. That is, the resist opens with an opening pattern, and the metal surface is exposed. Thereafter, a protective sheet is coated on the first non-etched surface. Here, the surface to be etched for the first time is defined as the front surface, and the surface that is coated with the protective sheet and not etched is defined as the back surface.

  The surface is etched, and a recess having a sidewall on the metal surface layer is provided. Thereafter, the resist on the etched surface is removed. Here, the shape of the hole can be increased to a high aspect by further deeply etching the deep layer portion of the opening formed by the first etching. In the case where further etching is required only for a desired portion of the deep layer portion, an electrodeposition resist or a liquid resist is coated on the metal surface from which the resist has been peeled off and the opening by etching to expose the desired portion. By exposing, developing, and etching the exposed portion, a high-aspect hole or a complicated three-dimensional shape having a plurality of depths in one opening can be obtained.

  Next, the metal surface from which the resist is peeled and the opening by etching are cast with an insulating resin. When the insulating resin is filled, the opening formed by etching may be sufficiently filled, or it may be filled more than the depth of the opening to cover the entire metal surface. Next, the protective sheet on the back surface is peeled off and etching is performed. If necessary, a plurality of etchings may be repeated as with the surface. The metal surface and the opening by etching are cast with an insulating resin. When the entire surface of the metal substrate is covered with the insulating resin, the surface coated with the insulating resin is polished when the wiring is taken out from the substrate surface. In this way, a wiring substrate using a metal as a core substrate is formed.

  By laminating a metal foil on the surface of the core substrate, and repeating patterning and etching, further complicated wiring can be laminated on the substrate. A multilayer substrate can also be made by producing a plurality of the core substrates and bonding them together.

  Prior to etching, a resist is coated on a part or the entire surface of the substrate. For the resist used in the first etching process, use a positive photoresist such as naphthoquinone azide or novolac resin, or a negative photoresist such as dichromate, polycinnamate vinyl or rubber azide. Can do. An electrodeposition resist may also be used. When coating a liquid photoresist, a commonly used photoresist coating method such as a spin coater, a roll coater, or a dip coater can be used. When a dry film resist is used, a laminator is used.

  Before etching, exposure and development are performed at a desired position with respect to the photoresist. When a photomask is used for exposure and then development is performed, a desired resist pattern is obtained. Since the photoresist is coated on the metal surface, a photoresist having an opening pattern is formed by exposure and development.

  After the resist pattern is obtained, the first etching is performed. A first recess is formed by this process. Examples of the etching material include ferric chloride solution and cupric chloride solution. Although the method for supplying the etching solution is arbitrary, spray etching is desirable.

  The photoresist attached to the metal material used in the etching may be peeled off. The peeling method is arbitrary. You may peel off using resist stripping solutions, such as a hot alkali solution and organic stripping. After the primary etching, a secondary resist is formed on the surface of the metal substrate if necessary. In order to form the secondary and subsequent resists, it is almost impossible to coat the resist with a uniform film thickness on a metal layer with an uneven surface having an etched surface.

   Therefore, an electrodeposition method or a liquid resist is used to solve the above problem. The electrodeposited photoresist is coated with a uniform film thickness on the metal surface irregularities caused by the first etching. Although the film thickness can be controlled by the dielectric constant of the material itself and the electrodeposition conditions, the film thickness is preferably 2 μm or more from the relationship of the mechanical strength of the soot generated by side etching, and 10 μm or less for forming a high-definition pattern. Is preferable.

   As a method for applying the liquid resist, a spin coater, a roll coater, a dip coater, and the like are conceivable. However, the resist accumulates on the uneven hole bottom after the primary etching, and it is difficult to coat with a uniform film thickness. Therefore, it is preferable to carry out by a spray method in which fine particles are uniformly applied to the uneven sidewall and the hole bottom. As with the electrodeposition method, the film pressure is preferably 2 μm or more from the viewpoint of the mechanical strength of the soot produced by side etching, and preferably 10 μm or less in order to form a high-definition pattern.

  The secondary photoresist can then be exposed and developed. In the exposure, a second photomask different from the first photomask can be used. The metal surface is exposed only at a desired portion of the half-etched wall in the first etching step. As the mask, a second photomask different from the first photomask is preferably used. It is preferable to perform alignment of the second photomask having a pattern different from the primary photomask and the first photomask manufactured by etching in all steps. The exposure is preferably performed using a parallel light source from above.

  After the above development, the second etching is performed. In the second etching step, the secondary photoresist is coated, so that a side wall of the metal material is prevented from being etched and etching is performed at a desired location to form a complicated and high-definition metal pattern. Secondary etching may be performed in the same manner as the primary etching step. For example, when the etching is performed with an etchant such as ferric chloride or cupric chloride as in the primary etching, a metal etching product having a complicated three-dimensional shape is obtained.

After the etching, the secondary photoresist is peeled off. Next, a resin or ceramic having an insulating property is filled in the etched surface which has been etched once or a plurality of times until the previous step. Examples of the insulating resin include polycarbonate resin, polysulfone resin, polyetherimide resin, thermoplastic polyimide resin, tetrafluoropolyethylene resin, hexafluoropolypropylene resin, polyetheretherketone resin, vinyl chloride resin, polyethylene resin, and the like. A plastic resin is mentioned.

  In addition, thermosetting resins that can form the required insulation and adhesion, such as epoxy resins, bismaleimide triazine resins, polyimide resins, phenol resins, polyether resins, melamine resins, or unvulcanized butadiene rubber, butyl rubber, Natural rubber, neoprene (registered trademark) rubber, silicone rubber and the like can also be used. The ceramic can be used as a slurry by adding an organic binder and solvent to a mixture of amorphous glass or crystallized glass powder and ceramic powder such as alumina. When the resin or ceramic is filled, the volume of the manufactured etching hole may be sufficiently filled, and the resin or ceramic may be applied to the entire substrate including the unetched surface.

  Thereafter, a curing process is performed according to the material such as drying, heat treatment, and UV irradiation. Here, when resin or ceramic is applied more than etching, the surface is polished until the surface layer of the metal layer comes out. Up to this step, one layer of the wiring board is completed.

  Here, when a new layer is added on the substrate to form a multilayer or a complicated structure, there are a method of forming a metal layer by plating and a method of bonding metal foils together. When performing plating, electroless plating is first performed on the surface to form a thin metal layer. Using this thin metal layer as an electrode, electrolytic plating is performed up to a set thickness. In the case of laminating and laminating metal layers, it is also possible to adhere the metal foil with a conductive adhesive.

  When patterning the formed metal layer, the type of the photoresist is not limited. Thereafter, the photoresist is patterned and etched. By repeating the process of pasting a new metal layer on the shape manufactured in the previous process and forming a pattern, it is possible to form a multilayer while forming a complicated shape.

FIG. 3 is a schematic view showing the steps of the manufacturing method of Example 1 in cross section. A commercially available negative dry film resist having a thickness of 20 μm was laminated on both surfaces of a 200 μm thick copper plate. Next, as for the front and back of the substrate, the surface to be etched first was the front side, and the surface to be etched was the back side. The front and back sides were aligned through a photomask having a slit pattern light-shielding portion with a width of 120 μm on the front and back sides, and exposed with ultraviolet rays of 50 mJ / m ² . Next, a negative photoresist opening pattern for the first etching step was formed by spray development of an alkaline aqueous solution and having the same dimensions as the first photomask. Since the first side is not etched on the back side, a protective sheet is laminated (see FIG. 3A).

  As a first etching step, a ferric chloride etching solution was spray-etched at 52 ° C., 0.2 MPa, and a specific gravity of 1.30 to form a half-etched portion after the first etching. (Refer to FIG. 3 (b)) Thereafter, it was washed with water and sprayed with an aqueous solution of caustic soda at 30 ° C. to peel off the negative photoresist.

Then, a positive electrodeposition photoresist was coated with a film thickness of 8 μm. Next, exposure was performed by aligning with the first recess through a second photomask having a 40 μm pattern opened at a pitch of 110 μm. Exposure was performed at 500 mJ / m ² , and after heat treatment at 120 ° C. for 15 minutes, spray development was performed with a sodium carbonate aqueous solution (see FIG. 3D).

  Further, the second etching was performed (see FIG. 3F), and the resist was peeled off.

An insulating resin is embedded in the metal surface on the front side and portions opened by the first and second etchings, heat-treated at 80 ° C. for 30 minutes and dried, and a protective sheet is laminated on the surface.

  Next, the protective sheet on the back side was peeled off, the back side was etched, and the part that was formed by the first etching and filled with the insulating resin was opened (see FIG. 3 (i)). Insulating resin was embedded in the metal surface on the back side and the portion opened by the etching in the previous step, dried after heat treatment. Here, the portion of the insulating resin protruding from the opening was buffed.

Copper electroless copper plating on the surface of the substrate and electrolytic plating were performed to deposit plated copper having a thickness of 50 μm. A negative film dry film resist was laminated on both sides of the substrate. Next, ultraviolet rays were exposed to 50 mJ / m ² through a photomask having patterns opened on the front and back at a pitch of 200 μm. Subsequently, it spray-developed with alkaline aqueous solution, and the ferric chloride etching liquid was spray-etched at 52 degreeC, 0.2 Mpa, and specific gravity 1.30, and the etching part was obtained. The photoresist was peeled off to produce a wiring board having a coaxial structure (see FIG. 3 (m)).

  FIG. 4 shows the steps of the manufacturing method of the second embodiment in cross section. The same process as in Example 1 was performed, the insulating resin was filled, and the substrate surface was polished. Note that the metal layer is left outside the portion that becomes the shield portion of the coaxial structure without etching. Here, a copper foil having a thickness of 50 μm was bonded to the substrate surface by thermocompression bonding. A wiring board structure having a coaxial wiring structure was mainly manufactured except for the signal line and the insulating layer of the shield part (see FIG. 4M).

  FIG. 5 is a schematic view showing the steps of the manufacturing method of Example 3 in cross section. This was carried out together with the formation of Example 1 to Example 3, and the difference was the shape of the portion where the back side was etched as shown in FIG. By forming such a structure, it was possible to form a structure having a signal line outlet for coaxial wiring on the surface of the wiring board. Similarly, a wiring board that can be connected to the upper and lower surfaces and a coaxial wiring board can be formed by forming the shape of the outlet on the surface.

FIG. 6 is a schematic view showing the steps of the manufacturing method of the fourth embodiment in cross section. A commercially available negative-type dry film resist was laminated on both sides of a 100 μm thick copper plate. The surface to be etched first is the front side, and the surface to be etched is the back side. A photomask having a circular shape with a diameter of 30 μm on the front side was exposed to 50 mJ / m ^{2 of} ultraviolet rays through a photomask having a pattern with a line width of 50 μm and a space width of 50 μm opened at a pitch of 100 μm on the back side. Next, a negative dry film resist pattern for the first etching step was formed by spray development of an alkaline aqueous solution and having the same dimensions as the first photomask. Since the first side is not etched on the back side, a protective sheet is laminated (see FIG. 6A).

  As a first etching step, a ferric chloride etching solution was spray-etched at 52 ° C., 0.2 MPa, and a specific gravity of 1.30 to form a half-etched portion after the first etching. Thereafter, it was washed with water and sprayed with caustic soda at 30 ° C. to peel off the negative photoresist (see FIG. 6C).

  An insulating resin is embedded in a portion opened by the metal surface on the back side, heat-treated at 120 ° C. for 15 minutes and dried, and a protective sheet is laminated on the surface.

Next, the protective sheet on the back side is peeled off and etching is performed. As an etching process, a ferric chloride etchant was spray-etched at 52 ° C., 0.2 MPa, and a specific gravity of 1.30 to open a portion formed by surface etching and filled with an insulating resin (FIG. 6 ( g
)reference). Insulating resin was embedded in the metal surface on the back side and the portion opened by the etching in the previous step, dried after heat treatment. Here, the portion of the insulating resin protruding from the opening was buffed.

  By performing the above steps, the lower layer wiring portion and the interlayer wiring portion in the multilayer wiring board could be collectively formed in the plane from the same metal layer by photoetching.

It is a process flow figure explaining the manufacturing method of the conventional coaxial wiring structure. FIG. 3 is a cross-sectional view of a state in which one coaxial wiring structure in the coaxial wiring structure is cut in a direction perpendicular to the longitudinal direction. It is a process flow figure explaining the manufacturing method of the wiring board which the circumference | surroundings of the coaxial wiring structure in this invention are comprised with insulating resin. It is a process flowchart explaining the manufacturing method of the wiring board by which the circumference | surroundings of the coaxial wiring structure in this invention are comprised. It is a process flow figure explaining the manufacturing method of the taking-out port of the wiring of the coaxial wiring structure in the present invention. It is a process flow figure explaining the manufacturing method of the wiring board which has a bump structure in this invention.

Explanation of symbols

1 Copper foil (metal layer)
2 Prepreg 3 Core substrate 4 First photoresist 5 Metal plate 6 Protective sheet 7 First etched surface (surface)
8 Second photoresist 9 Second etched surface (surface)
10 Etching surface (back side)
11 Insulating resin 12 Metal layer 13 Signal line 14 Shield electrode

Claims (13)

  A wiring board having a structure in which a metal layer is used as a core substrate, and this is formed by repeating photo-etching, casting of insulating resin, and bonding at least once or twice or more.   Surrounding the signal line with an insulating resin layer and covering the outside with an annular shield electrode, it has a coaxial wiring structure, and the interlayer connection is made between the upper and lower surfaces of the shield electrode in the direction orthogonal to the signal line of the coaxial wiring structure. The wiring board according to claim 1, wherein the wiring board is possible.   The wiring board according to claim 1, wherein there are a plurality of types of wiring diameters of the shield electrode portions in a direction orthogonal to the signal line of the coaxial wiring structure within the same substrate surface.   4. The wiring board according to claim 1, wherein the periphery of the coaxial wiring structure is made of an insulating resin.   4. The wiring board according to claim 1, wherein the periphery of the coaxial wiring structure is made of metal.   A semiconductor package comprising the wiring board according to claim 5.   A printed wiring board comprising the wiring board according to claim 5.   5. A wiring board, wherein a capacitor is formed at a coaxial wiring structure connection portion of the wiring board according to claim 4.   7. A semiconductor package, wherein a capacitor is formed in the coaxial wiring structure connection portion of the semiconductor package according to claim 6.   A printed wiring board, wherein a capacitor is formed at a coaxial wiring structure connection portion of the printed wiring board according to claim 7. Coating photoresist on both upper and lower surfaces of the metal foil;
Patterning the upper and lower surfaces of the metal foil so that the shield electrode side surface and the signal line are formed;
A process of attaching a protective sheet to the lower surface of the metal foil and forming the upper half of the shield electrode side surface and the signal line by etching the upper surface at least once,
A step of casting the surface of the etching surface and the upper surface of the metal foil formed in the previous step with an insulating resin;
Removing the protective sheet on the lower surface of the metal foil to form the shield electrode side surface and the lower half of the signal line;
A step of casting the surface of the etched surface and the lower surface of the metal foil formed in the previous step with an insulating resin;
Polishing the substrate surface to such an extent that the shield electrode side surface part appears;
A process of patterning the upper and lower surfaces of the shield electrode by attaching metal foil to the upper and lower surfaces of the substrate;
Etching process;
The manufacturing method of the wiring board of Claim 2 consisting of these. In the step of patterning and etching so that the side surface portion of the shield electrode and the signal line are formed, a first recess is formed by the first etching, and the electrodeposition resist or liquid is formed on the etching surface and the metal layer surface formed thereby. 12. The wiring board according to claim 11, further comprising a step of coating a resist, exposing and developing so as to open a portion between the side surface portion of the shield electrode and the signal line and a portion where no wiring is formed, and performing a second etching. Production method. Coating the photoresist on the upper and lower surfaces of the metal foil;
A step of patterning an interlayer wiring portion on the upper surface and an inner layer wiring on the lower surface;
Applying a protective sheet on one side and etching the opposite side,
A process of casting an etching surface and a metal surface made by this process with an insulating resin;
Etching the opposite side to form a wiring pattern of the interlayer wiring portion and the inner layer from the same metal foil by photoetching, and
A method of manufacturing a wiring board having a multilayer structure in which at least one type of diameter of an interlayer wiring portion exists in the same substrate surface.

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